Question:

I am seeing a new doctor, a GP, not an endocrinologist. I am 50 years old and have had diabetes for 40 years. For the past six years my kidneys have just been borderline for spilling proteins, which I think is a very long time to keep it at that level. My new MD wants to start me on Altace 2.5mg once a day, even though I have not been on any medication for this before. Could you please tell me if this medication is for kidneys and is this a high dose for me (I weigh 145 pounds). I am asking this because I do like this doctor, however, she gave me some incorrect medicine last week and I have had diabetes long enough to know when I picked it up that it would not be the correct medicine for me. If not, what medicines are used for “beginning stage” kidney disease? Thank you so much.

Answer:

This question addresses the considerations for preventing diabetic kidney disease in a person with very longstanding, presumably type 1, diabetes. There are some principles which are generalizable for all people with diabetes and some that are specific to this subset with diabetes for many years. It might modify the decision to know what, if any, other complications of diabetes this questioner has experienced. In monitoring the kidneys for damage due to diabetes, we use two general types of measures of kidney function: First, we use measures of how selective the kidney is in filtering the blood. If the kidney loses selectivity, it lets bigger molecules like proteins out of the blood and into the urine. We measure this as urinary protein. When we measure the specific protein albumin with a test that detects very small amounts (commonly but incorrectly referred to as “microalbumin”), that can detect an earlier stage of diabetic kidney damage. The other tests focus on measurement of the amount of filtration that the kidney is performing. This is reflected in the blood test called serum creatinine, or in a test which combines blood measurements with a measurement on urine collected for a 24 hour period called a creatinine clearance. These creatinine tests become abnormal much later in the course of diabetic kidney disease so they are useful for detecting later changes in the process. There is very good evidence that several classes of drugs, most notably angiotensin converting enzyme inhibitors (ACEIs) and angiotensin receptor blockers (ARBs) are protective against the progression of diabetic kidney disease. At the same time, there is evidence that diabetic kidney disease becomes advanced and dangerous only in about 1/3 of populations studied. If there is not marked kidney damage by about 20-25 years of type 1 diabetes, there is a much lower likelihood that that person will develop significant kidney damage. There are no studies on whether these drugs add any benefit for kidney damage in this population. Ramipril (the generic name for Altace) is in the ACEI class. It has been shown to not only protect against kidney damage but also against heart attacks. Many doctors suspect but nobody knows for sure whether that effect is generalizable to all the drugs in the ACEI and ARB classes. From the point of view of the kidney effect, my own bias is to give ACEI or ARB for kidney protection only if I see elevated blood pressure or early evidence of kidney damage such as too much albumin in the urine. I think that is best supported by past research, given the cost and risk for those who will not benefit. Some doctors (in my experience, more commonly primary care doctors than endocrinologists) put anybody with diabetes on one of these drugs, arguing that the cost and risk for treating somebody who will not benefit is acceptable. I think that you need to consider the potential for cardiovascular benefit in making a decision even if the kidney protective potential is small. Diabetes is an important cardiovascular risk factor. You can see that you would get different opinions from different doctors on this question. The dose of ramipril mentioned is a modest dose. You would want to be particularly alert to the rare possibility of an allergic reaction, particularly breathing or skin problems that could develop soon after starting the drug. The other side effect with ACEI in a small fraction of people is a cough which is usually just annoying but not dangerous. That cough goes away with with switching to another class of drugs, such as an ARB. On balance, I would go along with your doctor although for different reasons. 

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